Light-emitting diodes (LEDs) are used in displays for many different types of devices. The LED displays can be made from finFET structures composed of different materials, including gallium-nitride-on-silicon (GaN-on-Si) or sapphire.
The formation of the LEDs is a challenge. For example, GaN has both a lattice mismatch and a thermal mismatch with Si, which can cause stresses in the structure, e.g., warping and cracks in the Si wafer. Also, as the indium (In) concentration increases, the lattice mismatch between the GaN and Si also increases. Moreover, the solid solubility of In in GaN can be very low, which leads to a large amount of growth defects in the GaN.